Means for dividing fluids



April 18:, 1944. Q J sELVlG 2,346,795

' MEANS FOR DIVIDING FLU'IDS Filed April 29, 1942 FIG. I

INV-ENTOR .J. N. SEL I/IG' g R me n- M;

A TTORNEI Patented Apr. 18, 1944 John N. Selvig,

Westfield, N. 3., assignor to Western Electric Company, Incorporated, New York, N. Y., a. corporation of New York Application April 29, 1942, Serial No. 440,961

6 Claims.

This invention relates to means for dividing fluids, and more particularly to a self-cleaning member for parting a liquid carrying a burden of dispersed solid material and flowing against and past the member.

The discovery underlying the invention was made in connection with problems arising out of a need to part smoothly and accurately a sheet of water carrying in suspension a charge of dispersed fibrous material and flowing down through a wide and slightly inclined flat-bottomed trough, it being desired to part the sheet into a plurality of constantly equal flowing portions for distribution to a plurality of receiving members.

An object of the invention is to provide a solid member so conformed as to part a liquid flowing against and past the member smoothly and consistently with avoidance of self-generated disturbance of the parted flow and with avoidance of clogging and obstruction by more or less dispersed immiscible substance carried by the liquid.

With the above and other objects in view, the invention may be embodied in a member for parting a liquid moving against and past the same, which member is formed on the portion against which the liquid comes to be parted with a re-entrantly curved or concavely anti-streamlined face transverse to the direction of flow of the liquid and against which the liquid is parted in its flow.

Other objects and features of the inventionwill appear from the following detailed description of embodiments thereof taken in connection with the accompanying drawing, in which the same reference numerals are applied to identical parts in the several figures and in which Fig. 1 is a schematic representation in side elevation ofa portion of an apparatus embodying the invention;

Fig. 2 is a plan view of the showing of Fig. 1;

Fig, 3 is an enlarged detail View on the line 33 of Fig. 2, of the liquid dividing member of the invention;

Fig. 4 is a view on the line 4-4 of Fig. 3;

Fig. 5 is a view corresponding to Fig. 4 of a prior art dividing member; and

Fig. 6 is a view corresponding to Fig. 3 of the showing of Fig. 5.

In the apparatus schematically illustrated in Figs. 1 and 2, only so much is disclosed as is necessary for a full understanding of the present invention in its broad phases. The apparatus of Figs. 1 and 2 comprises a tank 20 having a vertical stationary baflle 2| therein. A

liquid consisting of water carrying dispersed wood pulp fibers, is supplied to the left side of the tank 20 from some source (not shown) through a delivery pipe 22. The liquid flows down under the baffle 2| and rises in the right side of the tank substantially without turbulence to overflow smoothly in a uniform sheet into and down along the broad, flat-bottomed, slightly sloping trough or chute 23. Three stationary liquid dividing members 24, identical in form and structure,'are stationarily mounted on the floor of the chute and divide the down flowing sheet of liquid into four streams of equal volume which fall respectively into the four compartments of the second trough 25 and are disposed of in manner not pertinent to the present invention and therefore not shown.

The present invention is particularly concerned with the form of the liquid dividing members 24. It is desired that each of these shall part the sheet of liquid flowing against it accurately, smoothly and without variation in order that each stream resulting from the division may be continuously constant in volume.

The normal method of accomplishing this would be to provide a dividing member I24 formed as illustrated in plan in Fig. 5. Members having the shape shown at I24 in Fig. 5 have long been used in analogous situations. The member I24 has a sharp vertical cutwater edge I29- and tapers convexly out to the main body of the divider wall. It is found that for the imme diate purpose in hand, i. e., dividing a flowing sheet of water charged with dispersed paper pulp wood fibers, the conventional form shown at I24 in Fig. 5 sufiers from two principal and characteristic disadvantages. One is that fibers driven by the current against the vertical dividing edge tend to catch on the'edge and hang there. Others are then caught and entangled with those first caught, others still with these, and so on, until a pile of snagged fibers is built up. This may grow until it bridges across to the next similar pile and blocks the flow. It may lop over and block one divided stream more than the other. It may lop over, be torn away, carried down one of the channels, and jam there. In short, this is intolerable if the even division into equal flows of unaltered liquid is desired. A second difliculty may arise due to a familiar phenomenon of fluid flow. This is the fact that when a fluid flows against a sharp, dividing edge, almost invariably there is a tendency to flutter. Either, as in the case of an organ pipe speaking, the current of fluid flutters over the stationary being tapered down, and is formed to present areentrantly curved or concave face 26 transverse to the direction of flow of the liquid instead of a single, sharp, dividing edge. The outer ends of the concave face preferably merge into the side walls 28 of the head 29 of the member 24, through convexly curved portions 21. The portions 27 are preferably of considerably smaller radius than the portion 26. In some instances the portions 2'! may be of relatively minute radius, or may be small flats, or even merely sharp edges. The essential feature is the relatively broad, concavely re-entrant face 2% transverse to the direction of flow.

When a dividing head as shown at 29 in Figs. 3 and 4 is used, the current running against the face 26 piles up in an abrupt, high standing wave 38in front of the face 26 and around the rounded corners 21. Thence it drops away with surprising steepness into a smooth, swift, level flow along the inwardly tapering sides 28 of the head 29 and on along the sides of the member 26. A complex eddying about one or more, more or less vertical axes takes place in the mass of liquid lifted into and flowing through the wave 39. The wave maintains its general shape and size substantially unchanged so long as the thickness and rate of flow of the sheet of liquid to it remain unchanged. It will vary in height, though not materially in form and character, if the thickness and rate of flow of the sheet vary. It is observed that a dividing head of such form is self-cleaning. The eddying in the wave 30 prevents the deposit of matter carried by the liquid on any portion of the head. In all instances so far observed, the eddying remains substantially constant so that the flow of liquid around each side and along the faces 28 remains constant. There does not appear to be any effect equivalent or analogous to the flutter of a fluid flowing against a sharp edge (e. g., edge I29 in Fig. 5). If the head 29 be symmetrical about a longitudinal central vertical plane, i. e., if the center or axis of the face 29 is in that plane and the axes of the portions 2? are equi-distant from that plane and the radii of the two portions 21 are mutually equal, the head 29 will divide the flow against it evenly and smoothly and unvaryingly, throwing the liquid to its two sides in identical fashion.

In the above embodiment of the invention, the self-scouring effect of the form of the dividing head 29 is evidently of chief practical importance. For this purpose it is essential that the liquid dividing face of the member be generally squarely transverse to the direction of flow of the liquid against it, as illustrated in Fig. 4.

What is claimed is:

1. A trough to carry a flow of liquid, in combination with means mounted in the trough to divide the flowing liquid into separate streams and comprising a stationary liquid dividing member elongated in the direction of flow and having the upstream end thereof fonmed with a reentrantly curved liquid dividing face transverse to the direction of flow.

2. A trough to carry a flow of liquid, in combination with means mounted in the trough to divide the flowing liquid into separate streams and comprising a stationary liquid dividing member elongated in the direction of flow and having the upstream end thereof formed with a trans: versely widened head portion having a re-entrantly curved liquid dividing face transverse to the direction of flow.

3. A trough to carry a flow of liquid, in combination with means mounted in the trough to divide the flowing liquid into separate streams and comprising a plurality of mutually parallel stationary liquid dividing members each elongated in the direction of flow and having the upstream end thereof formed with a re-entrantly curved liquid dividing face transverse to the direction of flow.

4. A trough to carry a flow of liquid, in combinationwith means mounted in the trough to divide the flowing liquid intoseparate streams and comprising a plurality of mutually parallel stationary liquid dividing members each elongated in the direction of flow and having the upstream end thereof formed with a re-entrantly curved liquid dividing face transverse to the direction of flow, some of the said members extending farther upstream than others.

5. A self-cleaning fluid dividing member for dividin into separate streams, a flow of fluid carrying a burden of finely divided solid material, the said member having a re-entrantly curved fluid dividing face transverse to the direction of flow.

6. A self-cleaning liquid dividing member for dividing ,into separate streams a flow of liquid carrying a burden of dispersed fibrous material, the said member having a re-entrantly curved liquid dividing face transverse to the direction of flow.

JOHN N. SELVIG. 

